And, I read that connecting and disconnecting new displays is instant (doesn't have anything to do with the audio device of course, which seems to be the problem in this case), so they've changed something in that regard.

Probably after Mavericks comes out. I can't say for sure, but generally speaking, devs aren't going to jump on these things until we know the problem is actually on our side and isn't just one of the many OS X bugs that you would expect to see in an OS developer beta. Plus, not all of our OS X devs have access to Mavericks.